The invention relates to a measuring instrument for detecting a force and to a method for detecting a force. In particular, the present invention relates to a measuring instrument and to a method for detecting a pedal force, exerted by a driver, in a vehicle.
Lately, particularly in the automotive field, ever-increasing numbers of electronic systems are being used, such as anti-lock brake systems, traction control systems, or electronic brake systems. Especially for electronic brake systems, it is necessary for the force exerted on the brake pedal by the driver to be detected as precisely as possible, so that in accordance with it, a braking instruction can be provided to the brake devices of the vehicle. Using known travel measuring devices is disadvantageous in the sense that a constant association of the ratio of the travel to the force is not possible. That is, what the driver is asking for cannot be learned on the basis of the travel signal. Moreover, this requires mounting on the foot pedal mechanism of the pedal, which can lead to unfavorable installation geometries in the area of the pedal. For vehicles with right-/left-hand drive and automatic/manual transmissions, a separate sensor must be kept on hand for the various geometries of the pedals involved.
Pressure measuring instruments are also known, which work by way of diaphragm deformation, for instance, or use piezoelectric elements. In the use of pressure measuring instruments for detecting the brake pedal force, however, it is disadvantageous that what the driver is asking for is not immediately obtainable. In addition, the (damping-dependent) dynamics of the pressure measuring instrument are relatively poor, and an output signal with relatively pronounced hysteresis is obtained.